I read an article that a Sweedish engineer a Mr. Loof Lirpa, using the theory that the Chinese junks have with holes in the rudder so it will go thru the water more efficiently, applied it to engine driven propellers in boats. Depending on the diameter, pitch, and peak rpm of the prop, Mr Lirpa drilled holes in each blade, effectively decreasing the horsepower needed to turn the prop therefore making the whole combination more efficient. Mr. Lirpa also stated that during his testing he noticed a drop in fuel consumption, with no loss in performance..
Drilling holes in props.
Rattlesnake Jake
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I read an article that a Sweedish engineer a Mr. Loof Lirpa, using the theory that the Chinese junks have with holes in the rudder so it will go thru the water more efficiently, applied it to engine driven propellers in boats. Depending on the diameter, pitch, and peak rpm of the prop, Mr Lirpa drilled holes in each blade, effectively decreasing the horsepower needed to turn the prop therefore making the whole combination more efficient. Mr. Lirpa also stated that during his testing he noticed a drop in fuel consumption, with no loss in performance..
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Boy, for being so early in the morning ,you guys are quick! :winker:
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Jake, you might be on to something. 
I'd use a buddys prop first.
Just for the he!! of it like to see what woud happen.
I'd use a buddys prop first.
Just for the he!! of it like to see what woud happen.
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Mike, I know a guy with a 18 ft. aluminum Starcraft fish boat with a 70 Evinrude that will try anything. I'll tell him about it. It'll be awhile before ice out so we're gonna have to wait for the results..noise pollution said:Jake, you might be on to something.
I'd use a buddys prop first.
Just for the he!! of it like to see what woud happen.
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:worthless
Julie
Julie
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We could take this science a step further ourselves. Someone drill some holes in thier hull...3" diameter should work for this test. Place a line of them about where steps would be along the V. 2 or 3 rows of 3" holes should allow drag to release and free up tension from the running surface exponetially...Let me know how much speed, effiecency, and fuel economy is gained and MAYBE I'll share my Nobel p-rize with ya
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Tell me you're drinking this early.. :shocked: :laugher: :laugher:RSCHAP1 said:
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True, I've spent some time in China and they carried this one step further. They have found if you remove the rudder completely , it decreases the rudder drag almost completely, it's a bit harder to dock and steer but does increase the fuel mileage and top end.Rattlesnake Jake said:
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